Process of preparing isoprene.



UNITED STATES PATENT OFFICE.

RICHARD B. EARLE, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO HOOD RUBBER COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION.

PROCESS OF PREPARING ISOIl-IRENE.

To all whom 2'25 may concern Be it known that I, RIoHAizn B. EARLE citizen of the United States, residing at Boston, Massachusetts, have invented certain new and useful Improvements in Processes of Preparing Isoprene, of which thefollowing is a specification. v

The object of the present invention is to provide an improved economical. andeflicient method of preparing isoprene, and the invention includes the method hereinafter described and particularly defined by the a-p pended claims.

Isoprene is an unsaturated hydrocarbon having the formula G l-I It has heretofore not been a useful substance on account of the high cost of production and has been best produced by the distillation of turpentine through red hot tubes.

The present process consists in a dry distillation of palmitate of dimethyl-ethylenecarbinol and the preparation of the same. This ester has the following formula:

CHsOzCm p mately 180 C. The liquid is then, after cooling, filtered off from the separated sodium chlorid and the alcohol distilled off, leaving the paimitate of dimethyl-ethylenecarbinol which is pure enough for my purpose. This substance is then directly distilled in any suitable vessel by any suitable Renewed May 16, 1912. Serial No.

tillation breaks down into isoprene' and palsource of heat, anddurin'gthe process of disv Specification of Letters Patent. Patented Jan. 14;, 1913.

7 No Drawing. Application filed November 12, 1910, Serial No. 592,101.

ratelycollected in suitable receiversfi During this distillation itisdesirable to ass a current of dry carbon di'oxidthroughfthe- I Theefliciency of the hereindescribedp'rot} apparatus.

ess is about Having described the inventionfl claim'as new:

- 1. A stepin the method oftproducing 'iso;

prene which consists in dry distilling climethyl-ethy1ene carbinol-palmitic ester.

2. The herein described method ofproducing isoprene which consists infirst heat.-

ing together chlor-trimethylethylene with sodium palmitate and alcohol to produce dimeth'yl ethylene carbinol palmitic ester,"

and then dry distilling said product.

. 3. The herein described method of preparing isoprene which consists in mixing together chlor-t-rimethylethylene and sodium palmitate and alcohol, heating the same in a closed vessel, cooling and filtering the same prene, the preparation of dimethyl-ethylene carbinol palmit-ic ester by heating together chlor-trimethylethylene" with sodium palmr,

tate and alcohol in a closed vessel.

In testimony whereof, I atiix my signature in presence of two witnesses.

RICHARD B. EARLE. Witnesses: a

JAMES M. SPEAK,

WILLIAM W. DUNCAN. 

